Standard 2-way Lighting Circuit using Fibaro Dimmer 2

IMPORTANT - Read this first!

Note: To simplify these diagrams, we have not shown the earth cables - but all circuits MUST have the earth cable correctly installed.

We've shown wires in red to indicate that they are new wires, but it doesn't really matter what colour you use.

To protect the module a suitable rated overcurrent protection fuse must be installed on the Live input.

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One of the things that confuses people the most is installing home automation into an existing 2-Way lighting system. This application note looks at how a Fibaro Dimmer 2 module can be installed to control a standard 2-Way lighting system.

Firstly, what do we mean by 2-Way lighting?

This simply refers to a lighting system where one light is controlled by two light switches. Examples of this are where a room has two entrances (each needs a light switch) or for a hall light that can be controlled from the hall and the upstairs landing.

For information on how to physically install a Z-Wave module take a look at our guide here.

To know more about how Z-Wave modules work with different switch types make sure to read our guide here.

Standard 2-Way Lighting Circuit

Figure 1: Standard 2-Way Lighting Circuit.

A 2-Core cable (brown and blue) carries the Live and Switched Live to the wall switch and up to the light fitting. An extra 3-Core cable (brown, black and grey) connects the two wall switches together, enabling each of them to independently turn the light On or Off.

This type of lighting system uses "Toggle" (latching) switches. These latch in position - for instance when you press the switch to On, the switch physically stays in the On position. These are the standard light switches you'll find already fitted in your home.

The module can also be used with a variety of "Momentary" switch types and configurations. Momentary switches, also known as Retractive or Bell-Push, only remain in the On state while you press them, they return to the Off state when the button is released.

This doesn't mean that you have to keep holding the button to keep the light on. The module's internal controls automatically keep the light on when the button is released.

More information about how the Fibaro Dimmer 2 works with different switch types is available here.

We can install the module into the 2-Way circuit in various different ways shown below. We've separated out the diagrams based on whether you need to install the module at Switch A or Switch B position.

Fibaro Dimmer 2 Connections

The Fibaro Dimmer 2 has six terminals to connect it to the electrical wiring:

L – Live

S2 – connection to Switch 2

S1 – connection to Switch 1

Sx – switch common

N – Neutral (this is connected to Sx in 2-wire installations)

~ (Output) – connected to light or load

Fibaro Dimmer 2 Parameter Setting:

The following parameters may need to be set:

20 - 0 - enables the module to work with momentary switch (default)

20 - 1 - enables the module to work with a toggle switch

20 - 2 - enables the module to work with a 3-position momentary switch

26 - 1 - enables the modules' S2 switch to also control the load (default 0)

Installation at Switch A position

This is probably the most common of requirements, you will install the module at the Switch A position where it has access to both the 2-Core wire and the 3-Core wire.

In this case we keep the standard Toggle switches connecting Switch A "L1" to the module's S1 input and Switch B "L1" to the module's S2 input with the "COM" wire connected to the module's Sx output. Any unused wires from the original 3-core between the two switches should be safely terminated.

The module is then configured to accept S2 as the second switch control of the module.

This gives simple On / Off control of the light from the switches but you will still be able to control the dimming level over Z-Wave if required.

Fibaro Dimmer 2 Parameter Setting:

The following parameters need to be set:

20 - 1 - enables the module to work with a toggle switch (default is 0 for a momentary switch)

26 - 1 - enables the modules' S2 switch to also control the dimmer (default 0)

By using Momentary switches, the 2-Way wiring can be simplified - simply connect both Switch A and Switch B "L1" to the module's S1 input and the "COM" wire to the module's Sx output. Any unused wires from the original 3-Core between the two switches should be safely terminated.

Fibaro Dimmer 2 Parameter Setting:

Using the module with Momentary switches enables the easy creation of 3-Way lighting circuits, in fact an infinite number of Momentary switches can be wired in parallel to create 3-, 4-, 5-, 6-way... lighting systems.

Fibaro Dimmer 2 Parameter Setting:

You can also use "3-position" Momentary switches in the same way with the module. These switches can give a more intuitive control for the user because it operates like a traditional rocker switch with up and down push positions which work well for dimming up, dimming down and on / off commands.

Figure 6: Using 3-Position Momentary switches with Fibaro Dimmer 2.

To install this type of switch you simply leave the 3-Core wired between the switches intact and connect the "L1" wire to the module's S1 input, the "L2" wire to the module's S2 input and the "COM" wire to the module's Sx output.

Fibaro Dimmer 2 Parameter Setting:

The following parameters need to be set:

20 - 2 - enables the module to work with a 3-position switch (default is 0 for a momentary switch)

Fibaro Dimmer 2 Parameter Setting:

Sometimes you may require a 2-Way or multi-way lighting circuit where physical wiring doesn't already exist, or perhaps you need to re-purpose the existing wiring for something else.

Z-Wave makes this possible using something known as "Associations" - where one Z-Wave device can control another Z-Wave device directly without inter-connecting wiring. More information on Associations can be seen in our guides here and here.

To create this circuit you simply install the module to suit either Toggle or Momentary switches and safely terminate the 3-Core cable as required. A battery powered Z-Wave wall switch such as the Nodon Wall Switch can then be Associated to the module.

Don't forget to configure the module for Toggle or Momentary switches!

Installation at Switch B position

In some circumstances it may not be possible to install the Fibaro Dimmer 2 module at the Switch A position - perhaps there's not enough room physically to install it there, or perhaps that position is out of range of the Z-Wave netwok. In this case sometimes it's possible to install at the Switch B position but there are a number of caveats because in this position it won't have access to both the 2-Core and 3-Core wire.

In this case we keep the standard Toggle switches, connecting Switch A "L1" to the module's S1 input and Switch B "L1" to the module's S2 input with the "COM" wire connected to the module's Sx output. We use the original "L2" wire to bring over Live from the first switch position and an additional wire is added to take Switched Live back.

The module is then configured to accept S2 as the second switch control of the module.

This gives simple On / Off control of the light from the switches but you will still be able to control the dimming level over Z-Wave if required.

Fibaro Dimmer 2 Parameter Setting:

The following parameters need to be set:

20 - 1 - enables the module to work with a toggle switch (default is 0 for a momentary switch)

26 - 1 - enables the modules' S2 switch to also control the dimmer (default 0)

Here we replace the standard Toggle switches with Momentary switches and connect both Switch A and Switch B "L1" to the module's S1 input and the "COM" wire to the module's Sx output. We use the original "L2" wire to bring over Live from the first switch position and an additional wire is added to take Switched Live back to the Load.

Connect Switch A “L1” to the module's S1 and Switch B "L1" to the module's S2 input with the "COM" wire to the module's Sx output. We use the original "L2" wire to bring over Live from the first switch position and re-wire Switched Live to the Switch B position.

The module is then configured to accept S2 as the second switch control of the module.

This gives simple On / Off control of the light from the switches but you will still be able to control the dimming level over Z-Wave if required.

Fibaro Dimmer 2 Parameter Setting:

The following parameters need to be set:

20 - 1 - enables the module to work with a toggle switch (default is 0 for a momentary switch)

26 - 1 - enables the modules' S2 switch to also control the dimmer (default 0)

Here we replace the standard Toggle switches with Momentary switches and connect both Switch A and Switch B "L1" to the module's S1 input and the "COM" wire to the module's Sx output. We use the original "L2" wire to bring over Live from the first switch position and re-wire Switched Live to the Switch B position.

Fibaro Dimmer 2 Parameter Setting:

Figure 13: Using a second Dimmer 2 S2 input in a Standard 2-Way Lighting Circuit with Fibaro Dimmer 2.

Here we replace Switch A with a Z-Wave Wall Switch. Connect Switch B “L1” to the module's S1 input with the "COM" wire connected to the module's Sx output. We use the original "L1" wire to bring over Live from the first switch position and re-wire “L2” to take Switched Live back to Switch A position. Any unused wires from the original 3-core between the two switches should be safely terminated.

A battery powered Z-Wave wall switch such as the Nodon Wall Switch can then be Associated to the module. More information on Associations can be seen in our guides here and here.

Here we connect Switch A “L1” to Module A S2 input. Connect Switch B “L1” to the Module B S1 input with the "COM" wire connected to the Module B Sx output. We use the original "L1" wire to bring over Live from the first switch position and re-wire “L2” to take Switched Live back to Switch A position. Any unused wires from the original 3-core between the two switches should be safely terminated.

More information on how to use a Secondary Switch with a Fibaro Dimmer 2 module can be found here.

Note: power to module at Switch A not shown as this would typically be taken care of for switching the other gang in a 2-gang switch.